S.C. Code Ann. § 62-3-406: Testimony of attesting witnesses.

In a contested case in which the proper execution of a will is at issue:

(1) if the will is self-proved pursuant to Section 62-2-503, the will satisfies the requirements for execution, subject to rebuttal, without the testimony of any attesting witness, upon filing the will and the acknowledgment and affidavits annexed or attached to it;

(2) if the will is notarized pursuant to Section 62-2-503(c), but not self-proved, there is a rebuttable presumption that the will satisfies the requirements for execution upon filing the will;

(3) if the will is witnessed pursuant to Section 62-2-502, but not notarized or self-proved, the testimony of at least one of the attesting witnesses is required to establish proper execution if the witness is within this State, competent, and able to testify. Proper execution may be established by other evidence, including an affidavit of an attesting witness. An attestation clause that is signed by the attesting witnesses raises a rebuttable presumption that the events recited in the clause occurred.